A pedestrian is seen at 14th Avenue and Yosemite Street in Denver, the site of a deadly hit-and-run accident that killed two young boys and seriously injured their mother on March 22. (Andy Cross, The Denver Post)

“It is a capital mistake to theorize before one has data,” Sherlock Holmes said in one of Sir Arthur Conan Doyle’s novels about the sleuthing Englishman.

Call this, then, the Case of the Missing Data.

Denver has been beset with a troubling spike in auto-pedestrian accidents in recent months. Yet it was made clear in a story by The Denver Post’s Joey Bunch last Sunday the transportation and public safety agencies that would have the data needed to help find ways to decrease such accidents aren’t regularly sharing and discussing the information.

That’s an anomaly among metropolitan areas, experts say.

“You need very detailed information from all kinds of sources just to start,” Dick Schaffer, a former bicycle- and pedestrian-safety specialist for the Federal Highway Administration, said. “I haven’t seen the commitment to that in Denver that I’ve seen in other big cities.”

Data from Denver Police compiled at the request of The Denver Post showed the number of auto-pedestrian accidents for the first four months of this year were almost 35 percent higher than the same period in 2010. Hit-and-run cases were up 55 percent over each of the prior four years.

The fatality cases this year included the heart-wrenching example of 8-year-old Za May Khan and his 6-year-old brother, Ah Zet, who were killed after being struck by a vehicle while crossing East 14th Avenue at Yosemite Street. The boys’ mother, Zama Bee Khan, was seriously injured but lived.

The hit-and-run driver fled and has not been identified yet.

Meanwhile, two East High School students were injured in auto-pedestrian accidents this year, one of those a hit-and-run case where the driver later turned herself in.

The city of Denver is spending millions on improved crosswalks with wider and more reflective lines, “walk” signs that take longer to change and more flashing lights in school zones. The city’s also launching a “Heads Up” campaign to get drivers, pedestrians and bicyclists to look out for one another.

Commendably, Colorado Department of Transportation officials have been taking steps to be more proactive on this issue. The department earlier this year organized a summit of transportation and public safety officials to examine pedestrian safety.

“In addition to hosting the summit, CDOT is looking at how to innovatively use funds from our Highway Safety Improvement Program to address issues of pedestrian safety this year,” department officials said in a statement.

The agency also said it is planning to work with other public entities to “annually collect, analyze and distribute” data on pedestrian safety.

Here’s hoping that increased efforts to share and dissect traffic safety data will save some lives.